Fuel injector for internal combustion engines



1959 R.-L. SHALLENBERG 2,872,247

FUEL INJECTOR FOR INTERNAL COMBUSTION ENGINES Original Filed July 3.1953 Q ZINVENTOR.

United States Patent FUEL INJECTOR FOR IYTERNAL COMBUSTION ENGINESRobert L. Shallenberg, Wheaton, 111., assignor to Inter rJiationalHarvester Company, a corporation of New ersey Original application July3, 1953, Serial No. 365,901,

now Patent No. 2,792,259, dated May 14, 1957. Divided and thisapplication February 21, 1957, Serial No. 641,697

3 Claims. (Cl. 299-1071) This invention concerns liquid fuel injectionnozzles for internal combustion engines and more particularly relates tosuch a nozzle incorporated into a unitary structure with a fuel meteringpumptherefor.

This application is a division of my co-pending application Serial No.365,901, filed July 3, 1953, now Patent No. 2,792,259.

A principal object of this invention is the provision of a fuel meteringand injection nozzle unit of simplified structure utilizing anarrangement wherein the fuel is metered at low pressure prior to beingsubjected to the relatively high injection pressure. Metering thereforecan be accomplished during a longer time interval which is conducive toaccuracy. This low pressure metering system also prolongs the usefulservice period of the unit since no metering surfaces of concentratedarea are subjected to the erosion of rapidly flowing fuel underextremely high pressure.

A further object is the provision of an improved fuel metering andinjection nozzle unit wherein the fuel pressure during metering isindependent of the injection pressure, wherefore the injection pressurecan be made as high as desired.

Another object is the provision of a fuel metering and injection nozzleunit settable to adapt low pressure flow of fuel therethrough toscavenge air from the fuel receiving passages and cavities thereof andthus efliciently prime the system for immediate starting of the enginewith initial cranking.

The above and other desirable objects inherent in and encompassed by theinvention are elucidated in the ensuing specification, the appendedclaims and the appended drawings, wherein: "Fig.1 is a longitudinalsectional view taken through a preferred embodiment of the invention;

Fig. 2 is a fragmentary sectional view taken at the plane indicated atthe line 2--2 in Fig. 1 to illustrate details of a control mechanism fora fuel metering elemerit of theunit;

Fig.3 is a longitudinal sectional view taken similarly I to Fig. 1through a second embodiment of the invention.

.Description of Figs. 1 and 2 embodiment With continued reference to thedrawings and particularly to Figs. 1 and 2, a fuel metering andinjection nozzle unit 21ais 'shownha'ving anelongated fabricated tubularbody 22a. An outer shell-like element 23a comprises part of the lowerportion of the tubular body 22a. This shell 23a has an opening 24a inits lower end. A nozzle member 2511, inserted through the upper open endof the shell 23 has a flange 26:: which abuts' against an inner face 27aof'the lower end of the shell 23a while the main portion'of the nozzlemember projects outwardly through the opening 24a. A tip-portion 28a ofthe nozzleelement 25a contains a plurality of discharge orifices 29aadapted to spray fuel in the form of atomized jets along respectivelyassociated median lines 30, Fig. 1, i to the u er part of a co bus o camber (not shown).

Patented Feb. 3, 1959 A cylindrical element 36a of the elongated tubularbody 22a has a flat annular lower end 37a which rests in sealed abuttingrelation upon the upper flat face of the nozzle element flange 26a. Thiscylindrical element 36a is telescoped downwardly into the inner bore 38aof the shell 23a after insertion of the nozzle element 25a into suchshell. The annular lower end face 37a of the cylinder 36a and the facewith which it abuts upon the flange 26a are lapped to effect a highdegree of smoothness of these surfaces to eliminate leakage of fluidtherebetween. A pump plunger or plunger structure 39a is inserteddownwardly into a plunger receiving bore 41:: formed by the innerperiphery of the cylindrical element 361:. A fabricated stem oroperating rod 42a for this plunger 39:: has a stern portion 43a formedintegrally with the plunger and projecting axially upwardly therefromthrough a cylindrical bearing 44a of a disk-like element 45:: whichforms an upper end for the plunger receiving bore 41a. A sealing O-ring46:: disposed within an annular groove 37a of the element 45a icompressed between the side wall of such groove and the outer peripheryof the stem 43a to supplement the sealing character of the bearing .4awith the stem. The lower end face of the element 45a and the upperannular end face of the cylindrical element 36a in abutment therewithare also lapped whereby they fit together in essentially perfectconformity to prevent leakage of fluid between these abutting surfaces.

An upper end portion of the stem 43a projects into a small diameterportion 48a of a recess 49a in the lower end of a push rod element 51aof the fabricated stern and operating rod 420. The rod 51a is connectedwith the stem 43a by means of an externally threaded sleeve nut 52aturned into an internally threaded portion 53a in a large diameter lowerportion 54:! of the recess 49a. The upper end of this sleeve nut pressesagainst a small snap ring 55a mounted within an annular groove 56acircumscribing the stem 43a. A lower end portion 57a of the sleeve nut52a has circumferentially arranged wrench-engaging facets (not shown)facilitating the turning of this nut for firmly advancing it endwiseinto the threaded recess 49a.

In the first embodiment of the invention, the fuel transfer passage 99::is formed within the pump plunger 39:: as distinguished from within thecylindrical element 36a. This fuel transfer passage 9% is an axiallyextension of a bore 970. which constitutes a combined fuel inlet andspill passage means within the fabricated stem and operating rodstructure 42a. The conical lower end portion 106a of the plunger 39a isformed separately from the main part of such plunger and has a stemportion 141 screwed into a threaded recess 142 in the lower end of theplunger. A portion of the transfer passage 99a is formed within theconical lower end portion of the plunger where such passage communicateswith the fuel delivery chamber 1030- through ports 1020. A check valve1011: within the transfer passage 99a comprises a ball 112a urgedagainst a seat 113a therefor by a spring 111a of suflicient strength torequire fluid pressure of approximately lbs. per square inch in theupper part of the transfer passage to unseat the ball.

Liquid fuel is forced into the unit under a relatively low constantpressure, 25 lbs. per square inch, for example, through a fuel inletchannel means 86a which communicates with a combined fuel inlet andspill cavity 63a through a port 143. A short cylindrical fuel blockingelement 144 of hexagonal or other suitable exterior faceted formationrests upon a shoulder 145 in the tubular body part 58a and because ofthe faceted outer periphery of this element 144 communication providingspaces 146 are formed between the lower end of this element and theshoulder 145 enabling fuel to flow downwardly through these spaces fromthe cavity 63a into a space 147 below a fuel blocking control edge 148of the element 144.

The axial position of the fuel metering element 95a is determined by acontrol rockshaft 114a having a manual or governor actuated arm 131aconstrained for rocking with its outer end. The inner end of the shaft114a has a circular head 149 having an operating pin 151 mounted thereineccentrically with respect to the axis of the shaft Tilda. This pinprojects into a circumferential groove 117a of the metering element 95aand is thus effective for raising or lowering said element #Sa when therockshaft 114a is rocked. A spring 120a reacts downwardly on theblocking element 144 and upwardly on the metering element 5a. A spacersleeve 152 surrounding the valve stem and operating rod structure 42a ismounted upon the lower end of the annular sealing element 64a and thusestablishes an upper limit for the movement of the fuel metering element95a. O-rings iia and 6% are associated with the sealing element 64a. Anannular clearance space 153 is provided between the spacer sleeve 152and the valve stem and operating rod structure 42a and this clearancespace communicates with the spill cavity 63:; through any desired numberof openings 154 in the spacer element.

Operation of the Figs. 1 and 2 embodiment The plunger stern andoperating rod structure 42a of this first embodiment is operatedalternately in opposite cndwise directions by a rocker arm (not shown)prcssable downwardly on the crown 79a of a spring cap 78a and by thespring 74a. it will be assumed that the plunger stem and operating rod42a is being advanced downwardly under the force of rocker arm pressureapplied to the upper end wall or crown 79a of the spring cup 78a. Duringthis rapid downward movement of the stem and rod structure 42a the pumpplunger 39a is forced downwardly to expel air-entrained liquid fuel fromthe fuel delivery chamber 103a outwardly through the fuel dischargeorifices 29a in the nozzle tip 28a. While the conical lower end 106a ofthe plunger is upon or adjacent to the conical lower periphery 107a ofthe fuel delivery chamber, the lower edge 155 of a fuel inlet groove orannulus 156 circumscribing the plunger stem and operating rod 42:: willbe disposed slightly below the lower control edge 143 of the fuelblocking element 144 wherewith fuel under a constant low pressure Withinthe space 147 is forced into the annulus 156 and through the fuel inletport 870 into the combined fuel inlet and spill passage in S 'i'a. Atthis time the fuel spill groove or annulus 96a will be masked by thefuel metering element 95a wherefore the fuel entering the passage 97athrough the inlet annulus 156 and port 87a: can flow only downwardlythrough such passage 97a and through the laterals 98a thereof into theexpanded chamber 88a of the metering pump 8%.

On the ensuing upward retractive stroke of the plunger, initialcontraction of the pumping chamber 88a causes a back surge of fluidupwardly through the passage 97a and outwardly through the inlet annulus156 until the lower edge 155 of this annulus moves upwardly intoregistry with the lower annular control edge 148 of the fuel blockingelement 144. When such registration occurs both the annuluses 156 and96a will be masked respectively by the elements 144 and 95a so thatcontinued retractive movement of the plunger develops suflicientpressure, approximately 100 lbs. per square inch, within the fueltransfer passage 99a for opening the check valve 101a and forcing fluidthrough the ports 102a into the fuel delivery chamber 103a. The pumpingrate of the fuel metering pump 8% is exceeded by that of the fuelinjection pump 104a so that air or hot gas from an associated enginecombustion chamber (not shown) passes through the fuel dischargeorifices 29a into the chamber 1030 for heating and mixing with the fuelbeing transferred into this chamber. The transfer of fuel from chamber88a into chamber 103a continues until the upper metering edge 108a ofthe spill groove Mia commences to rise above the metering edge 109a ofthe fuel metering element 950. When this occurs a wide opening issuddenly formed between the edges 108a and 199a of a considerablecurvilinear extent to allow rapid escape of fuel from the metering pump89a upwardly through the passage 97a, port 94a, groove 96a and ports 154into the clearance space 153 and outwardly through the openings 154 intothe spill cavity 63a. immediately upon movement of the spill edge 108aabove the fuel metering edge 109a the low pressure release thus affordedfor fuel pumped by the metering pump 89a will diminish the pressure inthe upper part of the fuel transfer passage 99:! to result ininstantaneous closing of the check valve 101a and termination of themetering period when no more fuel will be delivered into the deliverychamber 103a. Had the metering element a been in a lower position thespill edge 198a would have passed registration with the metering edge109a earlier to correspondingly shorten the effective metering strokeand cause a correspondingly smaller quantity of fuel to be metered andtransferred into the delivery chamber 103a. This completes the operatingcycle as the plunger reaches its upward stroke limit preparatory tobeing again forced downwardly for ejecting air mixed fuel from thedelivery chamber 103a through the fuel discharge orifices 29a.

The fact that this species of the invention provides no coolant cavityin the lower end of the structure, together with the fact that the fueltransfer passage 99a is placed within the plunger instead of within thewall of the tubular casing body 22a makes it possible for the outsidediameter of the cylindrical element 36a to be small. As a consequencethe shell or casing element 23a has a small outside diameter, thusresulting in an extremely slender unit requiring a relatively smallamount of space for the mounting thereof in the head of an enginecombustion chamber.

Description of the Fig. 3 embodiment This second embodiment of theinvention has numerous elements corresponding to respective elements inthe first embodiment and to expedite this disclosure these correspondingelements in the second embodiment will be designated by the samerespective reference numerals with the suffix b substituted for thesuflix a in the drawing without necessarily repeating them in thisdescription.

In this second embodiment an upper end portion 161 of the plunger 3% isof relatively larger diameter and serves to divide a larger diameterportion 162 of the plunger receiving bore 41b into a lower primarypumping chamber 163 and an upper secondary pumping chamber 164. Abearing element 45b forming the upper end wall for the chamber 164contains a plunger stem receiving bearing 44b in which a portion of apower drivable pump operating member in the form of a plunger operatingstem 42b projecting upwardly from the plunger 39b is in sliding sealingrelation. An internal shoulder 165 of the tubular body 22b cooperateswith a snap ring 166 in maintaining the bearing element 45b fixedaxially of said body.

Fuel inlet ports 167 communicate inwardly through the body with theprimary pumping chamber 163. These inlet ports 167 may be connected witha fuel supply through a conventional annular coupling fitting girdlingthe tubular casing part 58b and having an annular delivery ductregistering communicatively with such inlet ports. Communication fromthe pumping chamber 163 to the secondary pumping chamber 164 is hadthrough fuel conducting passages 168 and past a check valve 169comprising an annular wafer element ,171 liftable from an upper end face172 of the ,valve plunger enlargement 161.against the force of anannular spring element 173 which reacts upwardly against a snap ring 174mounted on the plunger operating stern 42b.

Operation of the Fig. 3 embodiment of the invention It will be assumedthat fuel under a modest constant pressure is being maintained in thepumping cham ber via the fuel inlet ports 167, and that a rocker arm(not shown) is being operated for forcing plungeroperating stern 42b andthe plunger 39b sharply downwardly for ejecting fuel from the fueldelivery chamber 103b outwardly through the orifices 2%. During thisdescent of the plunger 3% the secondary pumping chamberl64 will beexpanding to create a low pressure condition therein less than thepressure in the primary chamber 163 wherefore this pressure differentialacross the plunger end and portion 161 will cause opening of the checkvalve 169 and the conduction of fuel from chamber 163 through thepassages 168 into the secondary pumping chamber. Therefore, when theconical lower end 106b, of the plunger arrives in seating relation withthe conical lower end face 107]) of the fuel delivery chamber 103b,secondary pumping chamber 164 will contain a charge of liquid fuel.During the ensuing upward retractive stroke of the plunger 39b under theforce of the spring 74b fuel within the chamber 164 will be dischargedinwardly through stem ports 175 and downwardly through the fuel transferpassage 9% past the check valve 10112 and outwardly through the ports102b.into the fuel delivery chamber 103b. During this initial upwardmovement of the plunger 3911, the fuel discharged from the pumpingchamber 164 inwardly through the ports 175 cannot flow upwardly throughthe spill passage 97b because the spill annulus 96b associated with thespill port 9411 is masked by the sleevelike metering element 95b. Themetering period terminates with the arrival of the upper spill edge10811 of the annulus 96b in registry with the upper or metering edge 10%of the metering sleeve 95b. Further upward movement of the plunger tocarry the edge 10812 above the metering edge 10% enables the fuel tospill from the annulus 96b, thereby reducing the pressure in the fueltransfer passage 99b and permitting the check valve 101b to close.Thereupon nofurther fuel is transferred into the fuel delivery chamber1031). Earlier termination of the fuel metering period to cause asmaller quantity of fuel to be metered and transferred into the fueldelivery chamber 103b is accomplished by lowering the metering element95b whereby the spill edge 108i) arrives in registry with the meteringedge 10% after a shorter portion of the upward movement of the plunger.Fuel spilled from the spill annulus 96b enters the spill cavity 63b fromwhich it is conducted through a drain passage 12% back to the inlet sideof a supply pump (not shown) for maintaining the constant fuel pressurethrough the inlet ports 167 in the primary pumping chamber 163.

The metered fuel transferred through the passage 9% into the fueldelivery chamber 10% is injected through orifices 2% during the nextensuing downward advancement of the pump plunger.

The lower portion of this unit constituting the second embodiment ofthis invention, that is, that portion of the unit including shell 23band the parts embraced thereby are constructed very similarly to theparts embraced by the shell 23a of the first embodiment so that thissecond embodiment of the invention is also relatively slender foroccupying a small space within the head of an engine cylinder. Thisspecies of the invention has the advantage over the first embodimentthat the plunger 3% and the operating stem 42b therefor are formedintegrally, thus dispensing with the necessity of a joint structure suchas that utilizing the coupling nut 52a of the first embodiment.

Having thus described these two embodiments of the invention with theview of fully, clearly and concisely illustrating the same, I claim:

1. In a combined fuel metering and injection nozzle unit, a bodycontaining a bore with fuel pumping and delivery chambers spaced apartaxially therein, a plungerstem-receiving bearing of less diameter thanthe portion of said bore having the pumping chamber and extendingaxially of the bore from such chamber, fuel discharge orifice meanscommunicating outwardly from the fuel delivery chamber, a plungeraxially reciprocal in said bore and constituting a partition separatingsaid chambers from one another, a plunger-operating stem of lessdiameter than the plunger and projecting axially therefrom through thepumping chamber and through said bearing with which such stem is insliding sealing relation, a fuel inlet channel extending axially in saidstem into communication with the pumping chamber, a fuel transferpassage extending axially in the plunger and having ports respectivelycommunicating with said chambers, said plunger being axially retractableinto the pumping chamber to displace a metered quantity of fueltherefrom through the transfer passage into the delivery chamberattendant to expanding the delivery chamber to accommodate receptionthereby of the metered and transferred fuel, valve means in the transferpassage and preventing reverse flow of the transferred fueltherethrough, and the plunger being axially advanceable into thedelivery chamber to eject the metered and transferred fuel therefromthrough the discharge orifice means.

2. In a combined fuel metering and injection nozzle unit, a bodycontaining a bore with fuel pumping and delivery chambers spaced apartaxially therein, a plungerstem-receiving bearing of less diameter thanthe portion of said bore having the pumping chamber and extendingaxially of the bore from such chamber, fuel discharge orifice meanscommunicating outwardly from the fuel delivery chamber, a plungeraxially reciprocal in said bore and constituting a partition separatingsaid chambers from one another, a plunger-operating stem of lessdiameter than the plunger and projecting axially therefrom through thepumping chamber and through said bearing with which such a stem is insliding sealing relation, said stem being endwise movable to alternatelyeffect endwise advancement of the plunger into the delivery chamber andretraction thereof into the pumping chamber, a fuel transfer passageextending axially in the plunger communicatively between the chambers, acheck valve in said passage to accommodate flow of fuel therein onlyfrom the pumping chamber to the delivery chamber, a fuel spill portcommunicating outwardly through a side portion of the stem beyond theopposite end of said bearing with reference to the plunger, a fuel inletport also in a side portion of the stem beyond said opposite end of saidbearing, fuel inlet and spill passage means extending communicativelyfrom said ports axially through the stem into communication with thepumping chamber, a metering element in masking relation with the spillport and having a metering edge past which the stem moves the spill portduring retractive movement of the plunger and stem, a fuel blockingelement in masking relation with the fuel inlet port and having acontrol edge past which the stem moves the inlet port during advancementof the plunger into the delivery chamber to admit fuel through saidinlet port and passage means into the pumping chamber, the inlet portbeing moved retractively past the control edge into masked relation withthe blocking element during retraction of the stem and plunger whereuponsaid blocking and metering elements maintain the inlet and spill portsconcurrently masked during continuation of such retraction for a fuelpumping period terminated by eventual movement of the spill port intoregistry with the metering edge, the retracting plunger being operableduring such pumping period to displace fuel through the transfer passageand check valve into the expanding fuel delivery chamber, said meteringelement being adjustable axially of the stem to vary the time when thespill port retracts into registration with the metering edge to thusselectively vary the length of the pumping period and the amount of fueltransferred into the delivery chamber during plunger retraction, and theplunger being operable during its ensuing advancement to expel themetered and transferred fuel from the delivery chamber through thedischarge orifice means.

3. In a fuel metering and injection nozzle unit, an elongated bodyhaving a stepped plunger-receiving bore extending lengthwise therein, arelatively large diameter portion of the bore being spaced axially froman end of the body and a smaller diameter portion of the bore beinginterposed between the large diameter portion and said end of the body,a plunger reciprocal in said bore, said plunger having a smallerdiameter portion slidable in the small diameter portion of the bore andcooper-able therewith when spaced from said end of the body to form afuel delivery chamber, the body containing a fuel discharge orificecommunicating from said chamber outwardly through said end of the body,the plunger having a large diameter portion reciprocal in the largediameter bore portion and of less axial extent than said large diameterbore portion to divide the same into a primary pumping chamber disposedadjacently to the step of the stepped bore and a secondary pumpingchamber adjacently to opposite and large diameter end of said bore, thebody having a fuel inlet port communicative with the primary pumpingchamber, the body having a plungerstem-receiving bearing extendingaxially from the secondary pumping chamber and of less diameter thanthis secondary chamber, a plunger-operating stem projecting axially fromthe large diameter plunger portion through and in sliding sealingrelation with said bearing, a fuel spill port in a side of said stem onthe opposite side of the bearing from the secondary pumping chamber, aspill passage extending axially within said stem communicatively betweensaid port and the secondary chamber, a fuel transfer passage extendingaxially through the plunger communicatively between the secondarychamber and the fuel delivery chamber, a check valve in the transferpassage facilitating flow of fuel therethrough from the secondarychamber into the delivery chamber but preeluding reverse flow of fuelthrough the transfer passage, a fuel conducting passage communicatingthrough the large diameter plunger portion between the primary andsecondary pumping chambers, a check valve facilitating fuel flow throughthe conducting passage from the primary chamber to the secondary chamberbut precluding reverse flow through such conducting passage, a meteringelement in masking relation with said spill port and having a meteringedge at which the spill port becomes unmasked by the metering elementattendant to retractive axial movement of the plunger and stem adistance carrying such port into registry with said metering edge, saidstem being endwise movable to alternately effect endwise advancement ofthe plunger into the delivery chamber and retraction for withdrawing theplunger from the delivery chamber attendant to expanding the same, saidplunger being operable during a first retractive phase in an operatingcycle thereof to expand the primary pumping chamber attendant toaccommodating admittance of fuel thereinto through the fuel inlet port,the plunger being operable during a succeeding advancement phase in itsoperating cycle to contract the primary pumping chamber incident toforcing the fuel therefrom through the conducting passage and past thecheck valve associated therewith into the secondary chamber which isbeing concurrently expanded, the plunger being operable during anensuing retractive operational phase to pump fuel from the secondarypumping chamber through the transfer passage into the fuel deliverychamber until the retractive movement of the plunger carries the spillport into registry with the metering edge of the metering element, themetering element being adjustable axially of the plunger stem forselectively variably determining when fuel pumped from the secondarychamber can escape through the spill passage as an alternative to beingdisplaced through the transfer passage into the delivery chamber andthereby selectively determine the amount of fuel with which the deliverychamber is charged, and the plunger being operable during the ensuingadvancement phase to eject metered fuel charge from the delivery chamberthrough the discharge orifice.

References Cited in the file of this patent UNITED STATES PATENTS Re.23,862 Simon Aug. 31, 1954 2,589,505 Morris Mar. 18, 1952 2,792,259Shallenberg May 14, 1957

